Profile contour machine



April 23, 1957 E. c. PoLlDoR ETAL PROFILE coNToUR MACHINE Filed Jan. 21, 1949 12 Sheets-Sheet 1 April 23, 1957 E. c. PoLlDoR ETAI- 2,789,354

PROFILE: coNTouR MACHINE m Filed Jan. 21. 1949 12 sheets-sheet 2 April 23, 1957 l E. c, PoLlDoR ETAL 2,789,354

I PROFILE CONTOUR MACHINE E. c. PoLlDoR ETAL PROFILE coN'rouRv MACHINE April 23, 1957 I 12 Sheets-Sheet,v 4

Filed Jan. 21, 1949 [Klllf April 23, 1957 E. c. pompon ErAL 2,789,354

PROFILE CONTOUR MACHINE Filed Jan. 2l. 1949 1 2 Sheets-Sheet 5 April 23, 1957 E. c. PoLlDoR ET AL PROFILE cQN'roUR MACHINE Filgd Jan. 2;. 1949 12 Sheets-Sheet 6 s. w3 a IH@ w a g ,a aw ,JB Erf April 23, 1957 E. c. BQLIDOR ET AL 2,789,354

' PROFILE coNTouR MACHINE Filed Jan. 21, 1949 12 Sheets-Sheet 8 55' -I-P- 25 707 77. 706 707e:

April 23, 1957 E. c. PoLlDoR ETAL 2,789,354 4 l PROFILE coNTouR MACHINE:

Filed Jan. 21, 1949 12 sheets-sheet 9 April 23, 1957 E. c. PLlD-OR ET AL 2,789,354

PROFILE coNTouR MACHINE April 23, 1957 E. c. PoLlnoR ETAL PR01-ILE coNTouR MACHINE:

12 Sheets-Sheet 11 Filed Jan. 21, 1949 April 23, 1957 E. c. P'oLlDoR l-:TL

PROFILE CONTOUR MACHINE Filed Jan. 21,- 1949 INI/irons Eward callar, wel 1h30@ United States Patent O 2,789,354 PROFILE coN'roUR MACHINE Edward C. Polidor, Rochester, Willis De Boer, Williamsville, and Gilbert A. Betts, Eggertsville, N. Y., assignors, by mesne assignments, to Optical @aging Products, Inc., Rochester, N. Y., a corporation of New York Application January 21., 1949, Serial No. 72,004

23 Claims. (Cl. 331-23) This invention relates to the accurate checking of surfaces to determine their deviation from a selected standard. It is particularly useful in checking the accuracy of the blades of propellers, the vanes of turbines, the surfaces of dies, and Various surfaces of other objects where similar problems are encountered.

An object of the invention is to provide an improved and uniform, fast, accurate, relatively simple and in# expensive method of and apparatus for inspecting and checking the accuracy of surfaces of various objects in# cluding patterns, dies, blades, vanes and their deviation, if any, from a master chart or from a former condition.

Another object is to provide a fast, accurate and simple method of and apparatus for inspecting contour profiles, thickness, width, displacement or twist relationship, and the leading and trailing edges of turbine buckets, blades, nozzle vanes, master patterns or dies.

A further object is to provide an improved method and apparatus for inspecting any accessible surface of an Yobject to determine the variations of such surface from a standard for, or former condition of such surface; which will provide a permanent inspection record of every surface inspected; which enables comparison of similar surl face portions of a plurality of objects; which enables an operator to view simultaneously the entire contour pro-4 files of each surface gaged; which enables inspection and comparison at any desired magnification, which enables making permanent records for study or reference of surfaces of objects before and after test or regular uses therei of, or before and after various treatments of or operations on the objects; which does not require the services of highly skilled or trained operators; which employs relatively inexpensive and common optical projection devices; whichmay be used with either large or small objects; which makes unnecessary the use of expensive guillotine gages and which employs only simple and compact ap paratus.

Various other objects and advantages will be apparent from the following description of several embodiments ofy the invention, and the novel features will be particularly pointed out hereinafter in connection with the appended claims.

In the accompanying drawings:

Fig. l is a side elevation of a simple, hand operated machine embodying the invention and illustrating the basic principles thereof;

Fig. 2 is a plan of the same;

Fig. 3 is a sectional plan lof a portion of the same, the section being taken approximately along the line 3- of Fig. 1;

Fig. 4 is an enlarged view of a portion of a glass vplate with a scribing iilm thereon, and in which the film has been cut or Idrawn to define the outline of a blade section, and which is formed in the use of the apparatus shown in Figs. l to 3 Fig. 5 is a sectional elevation through the plate of Fig.

5--5 of Fig. 4;

2,789,354 Patented Apr. 23, 1957 lice Fig. 6 isa plan of a master chart having marked thereon the permissible tolerances for comparison with the outline formed in the lm on the plate shown in Fig. 4;

Fig. 7 is a plan of. two plates superposed for comparison purposes, one carrying the master chart of. Fig. 6 and the other carrying a scribed film such as that on theV plate of Fig. 4, as arranged for comparison purposes in an optical magnifying device that projects magnified images of these superposed outlines; v

Fig. 8 is a sectional elevation through these superposed plates, the section being taken approximately along th line 8 8 of Fig. 7; f v

Fig. 9 is a side elevation, with a part brokenr away, of another embodiment of the invention;

Fig.u 10 is a plan of the same;

Fig. 11 -is a plan of still another embodiment ofthe invention, and which represents a commercial and more practical embodiment of the invention;

Fig. 12 is a sectional elevation through a portion of the same, the section being taken approximately along the line 12-12 of Fig. 11;

Fig. 13 is a side elevation, partly in section, of another machine embodying the invention, somewhat similar to that shown in Figs. 11 and l2 but employing a rotating table for carrying the plates, with scribing films, successively through scribing positions, the view corresponding to a sectional elevation taken approximately along the line 13--13 of Fig. 14;

Fig. 14is a plan ofthe same; v

Fig. 14a is a plan of one of the plates having a pluralityof outlines defined thereon for the different sections of one blade and which may be employed on the rotating table;

Fig. 15 is an end elevation of the same, partly in section;

Fig. 16 is a sectional elevation through part of the machine shown in Figs. 13, 14, and 15;

Fig. 17 is a plan of a master chart of transparent material, carrying superposed outlines of different sections of the same blade, with permissible tolerance variations indicated;

Fig. 18 is a plan of a superposed chart and scribed lm which are to be compared by projecting images of both simultaneously on a screen;

Fig. 19 is a sectional elevation of such a master chart superposed with a scribed iilm, the section being taken approximately along the line 19-19 of Fig. 18;

Fig. 20 is a sectional elevation through the machine of Fig. 14, the section being taken approximately along the line 20-20 of Fig. 16;

Fig. 21 s a sectional lelevation through the same, the section being taken approximately along the line 21-21 of Fig. 20; A

Fig. 22 is a sectional elevation of a portion of the same, the section being taken approximately along the line 22--22 of Fig. 2l;

Fig. 23 is a bottom, sectional plan of a portion of the same, the section being taken approximately along the line 23-23 of Fig. 21 and looking upwardly in the direction of the arrow;

Fig. 24 is a diagram of the cable system employed in the embodiment of Figs. 20 to 23;

Fig. 25 is a sectional elevation through a portion of the mechanism shown in Fig. 16, the section being taken approximately along the line 25-25 of Fig. 16;

Fig. 26 is a plan of a table that may be employed with the machines of Figs. 16 and 20-23; and

Fig. 27 is a sectional elevation of the same, the section being taken approximately along the line 27--27 of Fig. 26.

In the` embodiment of the invention illustrated in Figs. `1 to 5, the machine includes a base 1 having thereon a' block`2, carrying in its upper face a recess 3 thatreceives eneaaee andtts` the base4 of a turbine blade 5 or similar object having Aface or'surface portions to be checked for accuracy. The blade 5 upstands from the block 2. Disposed also on the base 1 is a support 6 which carries a track bar 7 that is parallel to the base 1 andhas side surfaces or edges 8 and 9. A carriage or .traveler 10 is disposed over the track bar 7, and for thisV purpose has a channel in its lower face which fits and receives the bar 7 therewith.

Preferably ball bearings 11 are disposed between side edges 8 and 9 of the bar 7 and the sides of the recess inthe under face of 'the carriage 10, so that .the .carriage may ride freely and without playalong the bar 7. The carriage'10 inwturn` is provided with a guideway 12 which is inthe nature of a'channelin .its .upper face, and slidingly mounted. inthis `channel. is an element 13. ABall bearings 14 are disposed between the .sides of the `,guideway 12 and the element `13.so as: toprovide free ,travel of the element 13 without play. The yguideway M12-.isp at a differentlevel from the inverted channel which sets over'the bar7, and runs Vcrosswise of the -bar 7 so that the carriage 10`an'd element 13 both travel infhorizontal planes at approximately right angles` to each other.

The end of the element 13 nearest the bladeS `isprovided with an upstanding, tubular cylindrical boss 15. Slidable verticallyin the. passage of boss 15 is a post 16 having a liat side face area 17 which is drilled with a row of vertically spaced holes or recesses 19. Secured in the side of boss'15 is a spring pressed plunger 20, whcih is urged'yieldingly towards the .passage of theboss-15 and against the side'face 17. vThe inner end of the lplunger 20 is small enough to enter into one Vof the recesses 19, and thus hold the post 16 in any of several vertically adjusted positionsinto which it may be moved. The post 16 depends well belowthe element 13, and at its lower end rotatably mounts a roller or follower 21, see Fig. l, disposed along side the blade. By raising and lowering the post 16,`the roller 21 may be disposed along any portion of -the blade V5 between its ends, and this roller 21 may ride along'and in contact with a surfaceportion of the blade,across the facethereof, as the velement 13 vgoes back and'forth along the carriage l10 and the carriage 1.0 goes backV and forth along thebar 7.

'Rotatably'mounted in the other end of the element 13 is a vertically disposed shaft 22 lwhich is spring pressed downwardly Vfor limited vertical movement, and which at its upper end has a knurled button 23 by which the shaft 22 may be manuallyrotated, and which, -byengagement with- -the element `1.3 ,limits downward movement of shaft'22.V The lower end of the :shaft 22 carries `a .head 2,4, on the lower end face of which is mounted a scribing tool"2'5 eccentrically of the rotary axis of shaft22. This scribing tool will'be carried with the element k13 lback and forth inone direction and also in crosswise directions with the lcarriage .10, which gives the .scribing ztool r'the equivalent of a universal movement, in a plane. Asthe roller 21 goes across and in contact with a ,face ,of the blade 5, at any .transverse section thereof, i-t will ,partake of 'a universal movement in a horizontal plane that Ais transmitted to the rotatable tool 25.

Also mounted on the 'base 1 is a pedestal .26, which rotatably .supportsa turntable 27, the axis of they turntable being vertical and the upper face of the turntable being at. The ,pedestal 26 is positioned on the base withone side of a face of the turntable. passing beneath the .rotatable head 24. Mounted on the upper face of l.the turntable Ais a glass plate 28, having upon its upper face a scribing film 28a 'which is ,well known in vthe art. The scribing tool rests upon the tilm-carryingface .of the plate 28, so that asthe element 13 :moves indifferent crosswisedirections while Vthe l,follower 21 moves `Valong and in contact with a farceofthe blade 5, the scribing tool 25 will pursue a similar path over the face of the plate 28, and will..scribe in -the film 28a on the plate 28 an outline of the face .ofthe ,blade 5' contacted by .the

' tions are shown by the dot and dash lines 21a.

follower. Preferably, one manually rotates the button 23 continuously in the same direction while the roller 21 is being moved over a face of the blade 5, and this will scribe a line that somewhat resembles a helical spring that is flattened sidewise, but the edge of which corre sponds to the contour of a section of the blade 5. The cutter 25 is rotated in circles while it is moved progressively, and such a line is illustrated inl Fig. 14a.

The roller 24 is first moved horizontally across Vone face of the blade 5 while in contact with it, -so as'to scribe on the film a line 30 representing that surface, land then is passed along the opposite face -of the bladel vat the same section while rotating the shaft 22, and this causes asimilar line 30 to be drawn or scribed on the film of plate 2S to correspond to the other face of blade 5 at the same section.

Upon completion of this operation, the plunger 20 is pulled outwardly to release the post `16, Vand thenv the post is shifted vertically, such as into thel position shown by the dash lines in Fig. l, and then the operation is repeated to scribe on the plate 2S another outline 30 corresponding to the cross section at a different portion of the blade 5. It will be understood, however, that after each outline 30 has been scribed to correspond 'to any cross section of the blade 5the turntable 27'is rotated to bring a new or unmarked section of the plate 28 bcneath the path of the scribing tool-25.

These blades 5 are often partially and progressively twisted along their longitudinal axis so as to have the shape shown in Fig. 3, but this is typical of only Vone type of .such blade. The dot and dash lines crossing the blade 5 in Fig. l represent selected surface portions where one may desire to pass the roller 21inorder .to define on the film the outlines of the cross sections'of the blade at those portions.

. InFigs. 4 and 5 a portion of the plate 28 is illustrated, where the ycircular paths of the roller 21 at different posi- While the film on plate 2S will actually carry lines corresponding to the path of the rotating tool 2S while the tool is being moved linearly, the net result, if the rotation of the tool 25 is rapid enough, would be to entirely removerthe film to form the clear space 29, Fig. 4, which leavesin the center of the clear space the outline 30 that ,corresponds .to the cross section at one of the dot and dash' lines on the blade 5.

. In order to compare such an outline 30 with a master chart, this plate 28 is superposed over a master .chartin an toptical viewing or projecting device, .such as rprojecting lanterns once known as magic lanterns and` sometimes :as stereopticans. Such lanterns are used frequently itofproject enlarged images of lantern slides that are .disposed across the optical axis of a beam of light which is focused on a screen. One form of a master chart is shown inl Fig. A6, and ispreferably lmade of plate glass 32 having on a face thereof a `translucent film 33 carrying thereona diagram 34 formed of spaced equi-,distant lines, one within the other. The inner one of these lines represents the minimum possible dimensions for the blade 5 at the section 30, and the outer of those lines v34 represents the maximum. permissible dimensionsfor the same Asection ofthe blade 5. The film 33 maybe a scribing lrn'haw' ing lines 34 scribed thereon to represent the maximum.

and minimum dimensions of the outline 30 that .are permissible, but preferably the iilm 33 is a sheetof thin,

vellum .drawing paper which is cemented over its entire face area, while taut, to the glass plate. The lines 34 may then be drawn in India ink onthis vdrawinggpaper. These charts are also photographically reproduced when extreme accuracy is necessary having the lines on clear glass plates.

In Figs. 7 and 8 the master chart and the scribed olltnot shown. By holding these superposed plates (1thehartl avea-354 and scribed outline) ,over a light, the vertical, parallel lines 35 in Fig. 7 represent the shadow cast by the outline 30 upon the tilm or drawing paper 33, so that the outline of the shadow of the section represented by line 30 may be compared with the tolerance linesl 34. If the margin of the shadow corresponding to the outline 30 falls everywhere between the lines 35, then one knows that the cross section of the blade at the position where the outline 30 was made, due to the movements of the roller 21 over the faces of the blade, is accurate to the desired extent. If the blade is warped from that desired, then the shadow of the outline 30 may, at one or more portions of the chart, fall outside of the tolerance lines, and one may thus know at a glance whether or not the blade is within accepted accuracy. The parts shown in Figs. 1 and 2 represent one of the very simplest forms of the invention, but the mechanism shown in Figs. 9 to 27 is more satisfactory and convenient.

Referring next to Figs. 9 and l0, another embodiment of the invention is illustrated in which the blade which is to be checked for accuracy has its base 4 received and secured in a correspondingly shaped recess 3 in block 2. This block 2 is mounted on the base 36, and the latter slidingly mounts the carriage 37 for movement toward and from the block 2. For this purpose, the base 36 is provided with spaced, parallel side guide members 38 which define between them a channel 39 in which the carriage 37 may reciprocate while being confined to the .base 36. Preferably the channel 39 is undercut at the :sides so as to receive in the undercut portions, flanges 40 tthat project from the sides of the carriage 37. Upstanding :from the lcarriage 37 is a post 41 on which is rotatably mounted an upright sleeve 42 with a flange 43 at its lower end that rests upon a at upper surface 44 on the carriage 37.

This sleeve 42 extends Ito a level above the upper end of the blade 5 and there it carries a horizontally extending arm 45. The free end of the arm 45 carries an upright, tubular boss 46 with a vertical passage 47 therethrough from top to bottom. Detachably confined in the lower end of the passage 47 is a spindle 48, which at its lower end rotatably mounts a roller or follower 49 which corresponds to the roller or follower 21 of Figs. 1 and 2. A series of these spindles 48 are provided of different lengths, so that when they are inserted in succession in the passage 47, they will depend to different lengths along the side of the blade 5. These spindles 4S may be detachably held, one at a time, in the passage 47 in any suitable manner, such as by a spring pressed plunger, such as 20, Figs. l and 2, or by any other means commonly employed for latching a spindle in a socket.

Disposed in the upper half of the passage 47 is a short stub shaft 50 which rises above the lboss 46 and there carries a pulley 51 which is larger than the shaft, so that it rides upon the upper end of the boss 46. Mounted on the sleeve 42 at the side opposite the arm 45 is a small electric motor 52 having an upright rotating shaft 53 carrying a grooved pulley 54 at its upper end. An endless belt 55 passes along the pulleys 51 and 54 so that the motor will continuously rotate the pulley 51 as the ar-m 45 rocks about the post 41 as a fulcrum and the carriage 37 moves back and forth on the base 36.

Upstanding from an end of the base 36 is a column 56 which carries a horizontal arm 57 at its upper end. Secured in a recess in the underface of the arm 57, in any suitable manner, is a glass plate 58 that is provided on its lower face with a scribing film. This plate 58 is disposed over the pulley 51, as the carriage 57 is moved back and forth and the arm 45 is rocked sidewise back and forth. A scribing tool 59 is carried on the upper end face of the' pulley 51, and its engagement with the film on the underface of the plate 58 will cause the scribing of aline representing the path of travel of the cutter as it rotates while moving progressively in a linear direction. v With this arrangement the roller -or follower 49 may be brought into contact with a facel of blade and moved Vover and in contactvwith that face, during which time the carriage 37 may be moved slowly toward or away from vthe blade' in the direction of arrows P while one rocks the arm 45' contact with the opposite face of the blade 5 at the same.

horizontal cross section of that blade. By this arrangement the tool 59 will scribe on the film of the blade 58 a path which delineates the outline of a Icross section of the blade 5 in the zone or cross sectional portion over which the follower was moved. The motor- 52Amakes it unnecessary for one to manually rotate the marking or scribing tool while the roller or follower 49 is moving around the blade 5. In Figs. l to 5 as Well as in Figs. 9 and l() the roller or follower 21 or 49 hasY the same diameter as the diameter of the path of rotation of 'the marking or scribing tool, in order that the outline defined by the tool will correspond in size to the portion of the blade 5 over which the roller moves.

In referring next to the embodiment of the invention illustrated in Figs. ll and l2, the base 60 mounts the blade 5 in a block 2 as in Figs. l to 10. A carriage 61 extends crosswise of the base 60, and is mounted thereon for travel back and forth in the direction of the doubleheaded arrow 62. Any suitable means for slidingly mounting the carriage 61 to reciprocate toward and from the blade 5 may be employed, and since such details of carriage mounting have been disclosed in Figs. l and2 and are common in machine tools, they are not illustrated in detail in Figs. 1l and l2. Slidingly mounted on the carriage 61 are two travellers 63 amd64, and they reciprocate back and forth on the carriage 61 in the direction of the double-headed arrows and 66 respectively. These travellers 63 and 64 are not directly connected to each other, so that they may be independently moved back and forth.

The traveller 63 has an arm 67 which extends along a side of the blade 5 and rotatably mounts a roller4 68 which acts as a follower to ride along one face of the blade 5. Similarly the traveller 64 has an arm 69 which extends past the blade 5, at the other face, but the arm 69 is somewhat shorter than the arm 67, so that as the travellers 63 and 64 travel together with the carriage 6l, the free ends of the arms 67 and 69 will have one ahead of the other depending on the direction of travel.

The arm 69 carries a roller or follower 70 which is adapted to ride against the other face of the blade, but the rollers 63 and 70 are in the same horizontal planes, so that they will move along opposite sides of the blade 5 at the same cross section. The travellers 63 and 64 may move independently toward and from the blade 5, so that each roller 68 or 70 may maintain contact with a face of the blade 5 while they are travelling with the carriage 61 in a direction crosswise of the length of the. blade 5.

The arm 67 has a boot 71 at the side of the roller 68 towards the carriage 61, and the arm 60 has a boot or guard '72 between the roller 7 0 and the carriage 61. Each of these boots 71 and 72 extends towards the blade 5 at least to the axis of rotation of the roller. These boots engage with the blade as the rollers approach the blade and prevent the rollers from contacting the blade behind their centers. This makes it impossible for the rollers to be hooked around the edges of the blade during their travels.

The traveller 63 has an `arm 73 extending in the opposite direction from the arm 67 and its free end mounts a pulley 74 that carries amarker or scribing tool 75 on its lower face. The pulley 74 is threaded upon a reduced threaded end of a shaft 76 which extends vertically through a tubular boss 77 provided on the free end of Y 7 the-arm 73. This shaft 76' may 'be mounted inthe Uboss 77 by suitable needle bearings 78 that are arranged adjacentthe upper and lower ends of the boss 77, within the passage therethrough, and provide a rolling low friction bearing between the shaft and the boss. The shaft 76 is free to slide endwise to a limited extent during its rotation, and' theV pulley 74 may have a flange 79 which telescopes over the cylindrical lower en-d of the boss 77, as shown in Fig. 12. rI he pulley 74 may have a frustoconical socket 8i) which fits over a similarly shaped portion 81 of the shaft'76.

The shaft 76 at its upper end extends above the boss 77 and is there provided with an annular groove 82 in which is mounted a thrust ball bearing 83. This bearing 83 is carried in a yoke 84 which extends over the top of the l'boss 77 and there carries a pin 85. Pin 85 is threaded through the yoke S4 so as to extend parallel to the shaft 76 and extend to selected distances. The .boss 77"is provided with a passage 86 from top to bottom through which the pin S slides endwise. The lower end of the passage 86 is enlarged, as at 87, so as to receive a helical spring 88 which surrounds the lower end of the pin 85. The upper end of the spring 88 abuts against theginner end of the enlarged portion 87 of the passage 86, andthe other end of the spring bears against a transverse pin 89 on the pin 85. The spring 88 is under compression, so that by its reaction between the boss 77 and pin 89, it urges the pin 85 downwardly. Since the pin 85 is carried by the yoke 84, and the latter is carried on the upper end of the shaft 76, the spring 88 will urge the shaft 76 endwise and downwardly so as to carry the scribing tool 75 yieldingly against a scribing lilm on the upper face of a transparent plate 9). Plate 90 is carried by base in a horizontal position.

Mounted on one end of the carriage 61 is an electric motor 91 which has an upright, rotating shaft 92 carrying a small grooved pulley B at its upper end. Mounted on the carriage 61 is a shaft 94- which extends vertically and carries on its lower face a grooved pulley 95. An endless rubber belt 96 passes around the pulley 93 on the motor and around the pulley 9S. Shaft 9d is approximatcly midway between the ends of the carriage 61, or in direct lalinernent with the blade 5. The shaft 94 alsovcarries beneath the lower face of carriage 61 two grooved pulleys 7. An endless elastic belt 98 passes around one of these pulleys 9'? and around the pulley 74 so that the 4motor 9.1 through the belts 96 and 9S serve to rotate the pulley 74 and the scribing tool 75. By 'threading the pin S5 through the yoke or bacswardly, one may limit the possible movement of the shaft 76 toward the plate 9d, so that when the plate @il is removed the cutter cannot follow the plate 9i) beyond a certain distance. Similarly the other traveler 6ft has an arm 99 similar to the arm 73, and at its free end it carries a tubular boss 100 which is similar to boss '77.

'This boss '77 rotatably mounts a shaft 76 for rotation and endwise movement in the manner shown in section at the left of Fig. l2. rl'he shaft ".76 is mounted in the same manner shown at the left in Fig. l2, including the yoke 84, the pin and parts carried on the boss le@ which correspond to those carried on the boss 77, and have corresponding reference numbers. The pulley 161, which corresponds to the grooved pulley 74 has a scribing cutter 102 on its lower end face. An endless elastic belt 1493 passes around the other grooved pulley 97 on the shaft 94 and around the grooved pulley llllv on the lower end of the shaft 76 of boss 18d. Between the pulleys 37 and 101, the belt 193 passes around two idler pulleys iil and 105 which are rotatably mounted on the arm 9d.

lMounted in the boss iii-tl is a horizontally disposed shaft 106 which is rockable upon a horizontal axis below the arm 99. This shaft 106 at one end carries an arm 107 that extends beneath the lower end of the pin i5 in the boss 166. By rocking the shaft 2% the arm 167 will cam the pin S5 upwardly and lift the shaft 76 and Lil) efr-sasso* 8 tool 5102. A similar shaft; and arm are provided beneath the pin 85-'and bossk 77 so thatA pin 85 onarm 73 also maybe elevatedto lift the tool 75 from contact with the plate 90.

The elasticity of the endless belts 98 and 103, and the acute angles of their travel relatively vto the double headed arrows 62, will tend to pull the travellers 63 and 64 towardeach other with va yielding force so that the rollers or followers l68 and 70l Will be urged into contact with the opposite faces ofthe blade 5, and maintain that contact as the rollers roll acrossthe opposite faces of the blade 5. The rollers 68 and 7i) Yhave the same diameter as the paths of travel of the tools 75 and 102, and the tools 75 and 102 will, While rotating continuously, pursue paths over the tilmfcarrying face of vplate corresponding to the opposite faces of the blade, S with which the rollers 68 and 70 contact. These tools 75r and 192 will thus delineate on the film on plate 9i) an outline which has the shape and size of the cross section of the blade 5 where traversed by therollers 68 and 7i).

In operating this mechanism, the blade 5 is mounted on the base 60, the parts are brought into the positions shown in Figs. 1l and 12, but with both rollers 68 and 70 beyond one vertical edge of the blade 5, which would be to the left of the blade 5 in Fig. 11. The travellers 63 and 64 are drawn toward each other by the elasticity and angles of the belts 98 and 103, so that the rollers 68 and 70 may slightly overtravel or pass as the travellers 63 and 64 move toward each other. With the motor 93. running, the carriage 61 is moved to the right in Fig. 11. During such movement the roller 70 will first engage with an edge of bladel 5, and then pass along and in contact with one face of the blade. Shortly after the engagement of roller 70 with one face of the blade 5, the roller 68 will also engage with the same edge of the blade in the same cross section, and move along the opposite face of the blade 5 Vatthe same cross section, and in trailing relation to the roller 70..

The travellers 63 and 64 will be resiliently urged toward each other to keep the rollers 68 and 7i? in Contact with opposite faces of the blade 5, and the tools '75 and will be given paths corresponding to the paths of the rollers 68 and 7i) and will scribe those paths on the upper face of plate 96. The boots 71 and 72 will prevent the roller from being hooked around the first edge of the blade 5 to be engaged, serve to cam the rollers away from the blade until they approach it properly. The pins 8S will be kept elevated, by operation of shaft 166, while the rollers are brought towards the rst edge of the blade 5, and then are released so that the tools 75 and 102 will engage with the film on plate 99 during the travel of the carriage while the rollers 68 and 76 are in contact with the blade 5.

In the embodiment of the invention illustrated in Figs. 13, 14 and l5, the construction is generally similar to that shown in Figs. ll and l2 except that blade 5 is mounted in a fixture on its support 60 and that the mechanisrn is provided to mechanically move the platform 198 back and forth on the base 169, toward and from the blade 5; also the xed support for the film carrying glass plate is replaced by a turn table, so that a series of scribing plates may be moved in succession through scribing position. Since the scribing mechanism and blade support are generally similar to corresponding parts in Figs. 1l and l2, such corresponding parts have corresponding reference characters. ln this embodiment of the invention as shown in Figs. 13-15, the carriage 61 is mounted on thev platform li which is mounted on the box-like base 109 for movement back and forth in the direction of a double headed arrow 110, through suitable guideways provided on the base 199.

The top of the base 169 has a longitudinally extending slot 111, Figs. 13 and 15, and the platform 10S is provided with a depending post 112, Fig. 13, that extends downwardly through slot 111 into the base 109. The

base 109 is provided in its interior with a split bearing 113 that rotatably supports avshaft 114, and this shaft has integral collars 115 at the ends of the bearing which restrain endwise movement of the shaft 114 without inhibiting its rotary movement. The shaft 114 extends in a direction parallel to the direction of movement of the platform 118, and is threaded through a passage in the depending post 112, so that when the shaft is rotated, the post 112 will act as a nut and be moved slowly in one direction or other, depending on the direction of rotation of the shaft 114. Fixed on the other end of the shaft 114 is a bevel gear 116 which meshes with and is driven by a bevel gear 117 that is ixed on a shaft 118 that extends at right angles to the shaft 114 through the front of the box-like base 119.

On its exterior end the shaft 118 carries a hand wheel 1'19 having an operating handle 120 so that by turning the hand wheel 119, one may cause the platform 108 to move in either direction at a relatively slow rate of speed. This replaces the direct manual operation of the carriage 61 in Figs. 11 and 12.

The base 109, at the end remote from the upstanding blade 5, has a bearing boss 121 which rotatably supports an upright turntable shaft 122. The upper end of this shaft 122 is upwardly convergent, Fig. 15, and a turntable 123 has a tapered passage 124 at its center which fits over this upwardly convergent section of the shaft 122, so as to form a driving connection between them, yet permit lifting of the turntable separately from the shaft 122. The shaft 122 above the turntable, Fig. 13, is cylindrical, with a diameter equal to or smaller than the smaller end of the tapered portion, and rotatably mounted on this cylindrical upper end is a master chart holder 125, which is in the nature of an arm that extends radially from the shaft 122 and sweeps over the upper face of the turntable, slightly above the same. Detachably secured on the upper face of the turntable are a series of glass plates 126, Fig. 14, which move successively through scribing position beneath the pair of rotating tools 75 and 102.

The holder 125, at its free end, is provided with an aperture 127 which may be successively alined with the plates 126, as the turntable moves the plates 126 beneath the arm 125, or the holder 125 may be rotated about the shaft 122. A transparent master chart 128, Fig. 14, is secured on the arm 125 across the aperture 127, and therefore one may bring the master chart 128 over the outline in any plate 126 that is away from scribing position. The chart 128 carries thereon a series of diagrams 129 corresponding to the different cross sections of the blade whose outlines are to be defined on the plates 126 in succession. The followers 68 and '70 may also be mounted in the forked ends of rods 68a and 70a that are rotatably mounted in arms 67 and 69 respectively. Nuts 70b are confined in the arms 67 and 69 and threaded on rods 68a and 70a so that by turning the nuts 70b one may shift the followers 68 and 70 toward and from the blade 5.

In the embodiment of the invention illustrated in Figs. 16 and 20-23 inclusive, provision is made to simultaneously scribe the outlines of different cross sections of the upstanding blade at the same time upon films provided on opposite faces of a glass or other transparent plate. In this embodiment of the invention, the upstanding blade 5 is mounted on the base at one end thereof in the manner explained in the preceding figures. The base is a box-like element 130 having a platform or support 131, Fig. 20, at one end, on which the blade 5 is mounted. The base 130 also has a slot 132 in its top wall which is similar to the slot 111 of Fig. 13. Mounted on the upper face of the top wall of the base 130 are opposed guides 133 having undercut grooves 134 between which is received and guided the travelling platform 135 which corresponds to the platform 108 of Fig. 13.

Platform 135 has a depending lug 136 passing downwardly through the slot 132 and it is threaded over the threaded end of a shaft 137 which is rotatably mounted in-a split bearing 138 that depends from the top of the base and rotatably supports the shaft 137 in the same manner that the bearing 113 supported the shaft 114 in Fig. 13. Collars 138a on shaft 137 engage with ythe ends of the bearing 138 and prevent endwise movement of the shaft in the bearing. Thus, the means of moving the platform back and forth between the guides 133 is similar to that provided in Figs. 13, 14 and l5, except that instead of the bevel gears for rotating the shaft 137,` the bevel gear 116 of Fig. 13 is replaced by a pulley 139,. Fig. 20 which is xed on the shaft and which is driveni by an endless belt 140 that also passes around a pulley' 141, see Fig. 16. The pulley 141 is fixed on a shaft 142y which is driven through a safety clutch shown in Fig. 25

and suitable reduction gearing contained in a housing: 143, from an electric motor 144. The motor 144 is. connected to line wires L and L2 with a switch 145 in.

the line wire L.

The platform 135 is provided with laterally extending; arms 146 and 147, Fig. 16, that are turned upwardly' at their free ends and support a pair of plate-like bridges: 148 and 149, Fig. 2() that are arranged in superposed, vertically spaced relation. A traveller 150 is disposed beneath the bridge 148, and provided with a recess in its upper face which receives the bridge 148. Ball bearings 151 are provided between the side edges of the bridge 148 and the traveller 150 which confine the traveller 158 to the bridge while guiding it in movements in directions from end to end of that bridge. Similarly, a traveller 152 is disposed above the bridge 149 and is provided in its lower face with a recess that embraces the side edges of the bridge 149, with the bridge in the recess. Ball bearings 153 are disposed between the side edges of the bridge 149 and the side walls of the recess in traveller 152, so as to confine that traveller to that bridge and guide it in movements lengthwise along that bridge in directions from end to end thereof.

There are two travellers 150 on the bridge 148, and two travellers 152 on the bridge 149. The two travellers on each bridge correspond to the travellers 63 and 64 on a common bridge or carriage 61 of Figs. 11 and 12, and each of these travellers mounts at one end the roller or follower, as in Figs. l1 and 12, and at its other end the scribing tool. Each tool is mounted in the manner explained for the tools 75 and 102 of Figs. ll and 12, except that here the scribing tools and their mounts are inverted on the traveller 150 because ythe scribing tools on the travellers 150 will be upstanding. Parts correspending to those in Figs. 11 and 12 have corresponding reference numerals.

The arm 147, Fig. 16, at its free end also mounts an electric motor 154 which is disposed with its driving shaft 155 vertical, and with a grooved pulley 156 on the upper end of this shaft. An endless elastic belt 157 passes around the pulley 156 and also around a pulley 158. The pulley 158 is disposed approximately horizontally and provided with an upstanding hub 159 and a depending hub 160, both of which have separate peripheral grooves to serve as small pulleys. The ends of these hubs 159 and 160 are rotatably supported by a depending bearing from the bridge 149, and an upstanding bearing from the bridge 148. The grooves in the hub 159 act as driving pulleys that correspond to the pulleys 97 of Figs. 1l and l2, and drive the belts 98 and 103, Fig. 20, that rotate pulleys 74 and 101 that carry scribing tools, as in Figs. 1l and l2. These scribing tools 75 and 102 are yieldingly urged toward the glass plate 161, Fig. 20, which is supported on an upstanding structure 162 provided on the base 130. This plate 161 has a scribing film on each of its faces.

Similarly the grooves in the hub 160 also correspond avea-ssa lend of travellers 151i are inverted fromthose shown in Figs. 1l and 12, as well as those shown on the travellers 152 on the bridge 149. With this arrangement, the outline corresponding to one section of the upstanding blade may be scribed in the film on the upper-face of plate 161 at the same time that the cross section of another part of the blade 5 is scribed on the underface of the same plate 161.

One of the travellers 162, Fig. 21, is provided with a long depending pin 163 and the other traveller 152 with a shorter depending pin 164, both at the sarne side of the bridge 149. @ne of the travellers 151i is provided with a short upstanding pin 165, which is arranged end to end with the pin 163, when the superposed travellers 156 and 152 at that side of the machine are in supcrposed alined relation. Similarly7 the other traveller 15d at the opposite side of the machine is provided with a long upstanding pin 166, which isin end to end arrangement with the pin 16e of the traveller 152 that is immediately above and alined with it. The bridges 148 and 149, intermediate their ends, are connected by webs 167, see Figs. 2l and 22, which have ribs 168, Fig. 2l, extending from their faces and crosswise of the bridges. Each of these ribs 168 is provided with an aperture 169, Fig. 20, in which are slidingly supported two rack bars 171B and 171 that extend in directions lengthwise of the bridges. The apertures 169, Fig. 2i), in each rib are vertically spaced. The lower rack bar 171, Fig. 2l, is provided on a face thereof with rack teeth 172, Fig. 22, which mesh with a pinion 173 fixed on the upper end of a vertical shaft 174 which is rotatably mounted in the platform 135.

On the lower end of the shaft 174 is fixed a sprocket wheel 175. Also supported on the platform 135, Fig. 21, is a slow speed electric motor 176 with its armature Shaft opstanding and projecting upwardly through an aperture 177 in the platform 135. The upper end of the motor is received within the slot 132 in the top wall of the base 13), so that the motor may travel endwise with the platform 135. Fixed upon the upper end of the armature shaft 178 is a sprocket wheel 179, and an endless chain 180 passes around both sprocket wheels 175 and 179 so as to provide a driving connection between the motor 176 and the pinion 173 that meshes with the rack bar 171. The motor 176 is supplied with current from line wires L and L2, and a suitable switch 181 in line wire L makes it possible to start and stop the motor as desired.

The rack bar 171 is provided at the end opposite the rack teeth 172 with rack teeth 182 in its upper edge, which mesh with an idler `gear or pinion 133, Figs. 21 and 22, which is rotatably supported in a boss-like enlargement v184 in one of the ribs 68. The pinion or gear 183 also meshes with rack teeth 185 provided in the lower edge of the rack bar 170, so that when the lower rack bar 171 is operated endwise through the drive connection from the motor 17 6, the upper rack bar 170 will be given an equal movement in the opposite direction. The rack bar 17d at one end is provided with a lug 186 which is disposed to engage with both of the pins 164 and 166 and push them horizontally away from the center of the machine when the rack bar 171 is moved to the left in Fig. 2l.

The lower rack bar 171 is also provided with a lug 187 which engages with and pushes the pins 163 and 165 when the racl; bar 171 is moved to the left in Fig. 2l, so as to carry the pins 163 and 165 to the left at the same time that the lug 135 on the upper rack bar is carrying the pins l1(4 and 165 to the right in Fig. 21. Since the pins 163, 164, 16S and 166 are carried by the travellers, it .follows that the lug 187 in moving to theleftin Fig. 21 will carry Vthe left-hand superposed travellers 150 and 15,2 outwardly away from the center of the machine, at the'sarne tin e that the lug 186 through its engagement with the pins 164 and 166 moves the other pair of super- Cil 12 posed'travellersv 150 and 152 to the right in Fig. 2 1, which would be away from the center of the machine. This separation of the travellers 152 from each other, and the travellers from each other, serves to carry the followers Lon those travellers away from the object, such as the blade '5, of which the scribing will be made.

To move the travellers 152 toward each other, a systemof cablesoperated by a weightis provided. Referring first to Fig. 24, a suitable weight 188 has a pulley 189 at its upper end around which passes a cable 190. This weight is disposedrat one side of the machine, which is at the right in Fig. 21, and the cable passes over a pair of pulleys 191 and 192 provided at dilerentvlevels on the same side of the plat-form 135, such as at the corresponding ends of the bridges 148 and 149'. That stretch of the cable 19t) which passes over the upper pulley 192 then passes along the upper bridge 149, and its end 193 is coupled to the traveller 152 which is at the left in Fig. 21. The other stretch of the cable 1790, which passes over the roller 191, passes along the lower bridge 143 to the opposite end of the bridge there around a pulley 194, upwardly and over a roller 195, and then toward the right hand side of the bridge in Fig. 2l, where at 196 it is coupled to the traveller 152 whichis at the right in Fig. 21. The pull on the ends of the cable 190 caused by the weight 188 is effective to pull the travellers 152 toward each other and thus carry one pair of the followers or rollers toward the object or blade 5 from opposite sides.

Similarly another weight 197, Fig. 24, is also provided adjacent the weight 188, and at its upperfend is provided with pulley 198 around which passes another cable 199. One stretch of the cable 199 passes upwardly over a pulley 2Gb at one end of the upper bridge 149, then along the upper bridge to the opposite end of the bridge where it passes around a pulley 2191 which is horizontally alined with the pulley 195, then it passes downwardly to the -adjacent end of the lower bridge 148 where it passes around another pulley 202 carried on that end of the lower bridge, then towards the opposite end of that bridge where it terminates in a fastening 203 where it is coupled to the traveller 150 which is at the right in Fig. 2l. The other stretch of the cable 199 passes'around a pulley '294 proivided at the adjacent end of the lower bridge 148, then horizontally along that bridge andterminates in a fastener 205 which is coupled to the traveller 15d-'which is .at the left in Fig. 2l.

.From the diagram in Fig. 24 it will :be observed that the weight 197 similarly pulls toward each other the travellers 15d. When the motor 176, Fig. 21, is defenergized, the weights 188 yand 197 are free to urge toward each other the upper travellers 152, and the lower travellers 150. When this happens, the pins 163, 164, and 166 will push the rack bars 170 and 171 in opposite directions and slowly rotate the motor 176 in opposite direction which serves as a slight brake to retard the approach of the traveller 152 and of the traveller y15).

Referring next to Figs. 16, 2O and 25, the pulley 141 is loose on the shaft 142 and fixed to one face of the pulley 141, Fig. 25, is a boss 266. Fixed on the shaft 142 is a sleeve 2117 which has a head 208 that abuts endwise against the free or outer end face of the boss 206. Secured in the end face of the head 208 which abuts against the boss 296, are clutch balls 269 which are provided in recesses 2141 in the head 208 and pressed by springs 21011 in an outward direction so as to project slightly beyond the end face of the head 208 and against Ythe abutting end face of the boss 206. The outer end of each recess 210 is slightly restricted so that the balls 299 cannot be fully 'ejected from the recess. The boss 206 is provided in its free end face with cavities or recesses intov which the balls 2119 are projected so as to provide a yield- .able driving coupling between the shaft142 and the pulley 141. This serves as a safety clutch which prevents 13 injury to the motor if endwise movement of the platform is prevented at any time.

It has been observed that with the apparatus of Figs. 16 and 20-25, one may simultaneously scribe 4different outlines on the films on opposite faces of the plate 161, Fig. 20, and the manner in whichY such a double coated plate 161 is employed is illustrated in Figs. 17 to 19. After the outlines corresponding to the different cross sections of the blade have been formed in the lms of plate 161, that plate 161 is removed from the machine and disposed beneath a master chart 211 which is similar to the master chart illustrated and described in Figs. 5 and 6. The master chart has its face carrying the diagrams or outlines 212 and 213 abutting against a face of the plate 161, as shown in Fig. 19, and the master chart and one of the films on plate 161 have set lines 214 and 215, see Fig.v 18, which should be brought into register when the master chart 211 is superposed on the plate 161. That is, the marks 214 on the chart 211 and plate 161 should be brought into register and also the other lines 215 on the chart 211 and the plate 161 also should be brought into register.

If these superposed chart and plate are placed across abeam of light the outline 216 of one face of the plate 161, which represents the actual outline of one cross section of the blade 5, will cast a shadow represented by the vertical shade lines 217 in Fig. 18, which will be in an approximate alinement with the outline markings 212 on the master chart. The markings 212 are spaced lines representing the maximum and minimum possible sizes for the cross section represented in outline by the outline 216, in the film of plate 161, and if the margin of the shadow cast by the outline 216 falls entirely between the two lines a and b, Fig. 17, then one knows that the actual cross section of the blade 5 represented by the outline 216 is accurate within permissible tolerances.

Similarly, the outline 218 on the other face of plate 161 and which represents the shape of another cross section of the blade 5, will cast a shadow approximately coinciding with the outline 213 on the chart 211, this shadow being represented by the horizontal shade lines 219 in Fig. 18. While the chart 213 may have continuous, equally spaced lines, as in the chart 212, to represent the tolerance variations, this outline 213, as shown, represents another manner in which the tolerance limits may be indicated. In this example the outline 213 represents the desired, accurate outline of the section of the blade represented by the scribed outline 218 on plate 161, and the tolerance limits along this outline 213 are shown as spaced parallel lines 220 on opposite sides of the continuous line. If the shadow cast by the outline 218 approximately conforms to the outline 213 on the chart and does not deviate therefrom in either direction further than the lines 220, then one knows by a glance that the blade section represented by the outline 218 is accurate within permissible tolerances.

Referring next to Figs. 26 and 27, a slight modification of machine illustrated in Figs. 16 and 20-25 is illustrated in which the plate 161 is replaced by a circular glass plate 221 which is mounted on the upper end of an upright spindle 222. This spindle has a head or collar 223 against which the plate 221 rests, the plate 221 having an aperture which fits over the upper end of the spindle 222. A split washer 224 is disposed on the spindle 222, and rests against the upper face of the plate 221. A nut 225, threaded upon the upper end of the spindle 222, clamps the Washer 224 against the plate 211 and confines the latter against the collar or head 223. The spindle 222 is rotatably supported by ball bearings 226 in a supporting frame 227 which is carried by the base 130.

Two` arms 228 radiate from the 'frame 227 tothe periphery of the disk or plate 221 and there carry screws 229. These screws 229 confine short at strips 230 against the upper face of the peripheral marginal edge of 14 the plate 221. By tightening the screws 229, the plate 221 and the spindle 222 may be confined against rotation. The portion of the plate 221 at one side of the spindle 222 extends beneath the upper scribing cutters, and above the' lower scribing cutters, in the position occupied by the plate 161 in Fig. 20. This plate or disk 221 is provided with scribing films on its upper and lower faces, and thus one may scribe on those faces the outlines of two cross sections of the blade 5 simultaneously, and after one pair of outlines have been formed thereon, as shown in Fig. 26, one replaces the blade with another and scribes the outlines of its similar sections on the tilms of plate 221, merely by rotating the disk 221, step by step through small increments after each scribing, so that the cross sections of successive blades will be arranged in sequence on the disk 221.

The base also carries beneath the edge of disk or plate 211, Figs. 26 and 27, at the side remote from the scribing position, a support 231 for a master chart 232 carrying outlines 233 and 234 representing the proper shapes of the sections of the blades that are scribed on the opposite faces of the plate 21. As the disk 221 is rotated step by step, the scribed outlines may be brought, in succession, beneath this master chart, and inspected, and thus one master chart serves as a convenient reference for a series of outlines of successive blades.

It is believed that the operation of the device will be clear from the foregoing description, but will be briefly summarized. In the simple machine illustrated in Figs. l and 2, the blade 5 is mounted in an upright position, and the glass plate 28 with the scribing film on its upper face is mounted on the turntable 27. The operator grasps the element 13, which may have an aperture A therein to serve as a handle, and moves the element to engage the roller or follower 21 with a face of the blade and then across that face while keeping the roller 21 in contact with that face. Then the roller is similarly moved in the opposite direction along the opposite face of that blade. During this movement, the operator also with the other hand, grasps the knurled button 23 and turns it continuously, which rotates the head 24 and its scribing tool 25, so that the tool will mark in the film a line representing circular and linear paths of movement combined, and the tangent to these paths defines an outline of the exact size and shape as the cross section of the blade 5 around which the roller 21 was moved.

The operator then shifts the post 16 vertically to another section of the blade 15, which one desires to measure, and the turntable 27 is also rotated to bring a fresh portion of the film 28 beneath the scribing tool 25. The same operation is repeated, and in the same manner another outline is formed representing the other cross section of the blade. Such an outline is shown in Fig. 4, and then a master chart shown in Fig. 6 is superposed on the outline shown in Fig. 4, .as shown in Fig. 8. Then, when the superposed plates are disposed across a beam of light, the outline 30 of Fig. 4, which represents the cross section of the blade, will project a shadow on the master chart, as shown in Fig. 7, which enables one to determine at a glance whether or not the cross section of the blade is accurate within permissible tolerances.

It will be understood of course that both the plate 28 and master chart have suitable set lines B and C which should be brought into register as a guide when superposing the chart and film-carrying plate. If the beam of light is that of an optical system, that magnities the shadow and the shadow is cast upon an optical screen and accurate comparison can be quickly made.

In the embodiment of the invention illustrated in Figs. 9 and l0, an improvement over the hand operation is provided, in that the motor 52 acting through the belt 55 continuously rotates the scribing tool that marks its lines on the film provided on the underface of the glass plate 58. In this instance there is only one sliding mounting, which is between rthe carriage 37 and the base 36, and

.ef/sash;

the scribing tool and follower are both mounted fon a pivoted arm 45. The rocking of the arm 45 allows the roller 49 to follow the surface of the blade as it progresses across the face of the blade.

In the embodiments of the invention illustrated in Figs. ll and 12, also 13 .and 14, provision is made to move followers over both faces of the blade in a single operation of the carriage or platfonm, so that by a single movement of the carriage 6, Figs. 11 and l2, or platform 108, to the right in Figs. ll and l2, both halves of the outline representing the cross section of the blade engaged by the followers will be formed on the scribing film. The travellers are urged toward each other by the elasticity of the belts that rotate the scribing tools.

In Figs. ll and 12 there are two travellers 3 and 64 mounted on a single carriage, so that the travellers may approach each other and recede while the carriage is travelling in a straight line path, which would be to the vright in Fig. 1l. The rollers or followers 68 and 70 snccessively engage with opposite faces of the blade and travel across them, and these followers are kept in Contact with the plate faces by reason of the elasticity and angles of the belts 9S and 103 which drive the scribing cutters, and which are driven from the common motor 91 continuously. The rotating scribing tools or markers are yieldingly pressed against the film or record sheet carrying7 plate 9i) by the springs 88, yet the cutters may be lifted from contact with the plate while moving the carriage into a position to start the contact of the roller 70 with the blade 5. The travellers 63 and 64 will thus be held in contact with the blade 5 as the carriage 61 moves to the right in Fig. 11,.

so that the pair of scribing tools will successively define the outline representing a cross section of the blade 5.

in Figs. 13 and 14, the platform 108, which corresponds to the carriage 61, is moved progressively to the right (Figs. 13 and 14), by merely turning the hand Wheel 119. This embodiment also illustrates the mounting of successive plates on a common turntable so that they may ble brought successively into scribing positions, and also illustrates how .the master chart can be mounted .above the turntable so that it can be brought over any scribed plate for comparison of the scribed outline with ythe outline pnovided on the chart.

ln Figs. 16 and 20-25, a more involved machine is illustrated, which simultaneously scribes the outlines of two cross sections of the blade at the same time on films provided on opposite sides of a glass plate, and the platform of a slow speed motor, and are urged in directions to keep their followers in contact with the plate by weights and cable systems shown in Fig. 24.

in Figs. 26 and 27 the machine is similar toi-that just described except that a circular disk or glass plate having films on its opposite faces is moved step by step through y scribing position, and then through viewing position over a master chart.

in the embodiment illustrated in Figs. ll and l2, the shaft 196 was provided with an ami 107 that engaged beneath each pin 85 so as to withdraw the scribing tool from contact with the film-carrying plate, when one d esired t-o move the tools over the surface of the plate or shift the plate to a new position. 106 is illustrated as extending along its related traveller towards the carriage 6i. Bearings 63a may be providedon each traveller to support the shaft 1G36, and adjacent the carriage di. the shaft 1&6 carries an arm 167:1 (Fig. l5 also) which may be engaged with a cam when the traveller has been moved away from scribing position on the carriage, 'f his is illustrated in Figs. l5 and i6, where it will be observed that the arm M17@ extends parallel to the direction of travel of the traveller for a substantial distance, and at its end is bent laterally at an acute angle to form `a cam surface 107i.

Provided on the carriage or platform is a pin 167C.

ln Pig. 13, this shaftY When the travellers are separated a distance beyond the zone where, there is desired contact with the scribing plate, the cam ends 10721 are cammed aside by the pins 107e and the pins 107e have relative movement along the lengths 'of the arm 107:1 to hold them in the same locked position as the traveller moves along the bridge or support. When any pin 107e locks the arm 10711, it serves to retract by its arm 107 the related scribing tool, so that holding the arm 107a by pin 107e in the rocked position serves to keep the scribing tool outof contact with the film until the scribing tool returns approximately to the position where a roller or follower is about to engage the blade. When the arm 107a is released from pin 107C, the spring 88 associated with each shaft '76 that carries a tool, will urge the tool into engagement with the lm on the scribing plate.

It will be understood that various changes in the details yand arrangements of parts, which have beenherein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principal and scope of the invention, as expressed in the appended claims.

We claim: 1. In the method of comparing the profile contour of a selected portion of an object with a master chart of said portion and carrying thereon markings indicating permissible deviations therefrom, that improvement relating to the preparation of an outline of said surface for optical comparison withV said chart, which, comprises simultaneously rolling `roller followers entirely across and in contact with opposite meeting faces of said object portion in the same transverse plane, with one follower leading the other, and the paths of the followers crossing at opposite sides of said object, and simultaneously recording in the same order on a film, lines corresponding to the relative paths of said followers in the same relationship to each other and positions as said paths and similarly crossing. 2. In the method of comparing the profile contour of a selected portion of an object with a master chart of said portion and carrying thereon markings indicating permissible deviations therefrom, that improvement relating to the preparation of an outline of -said surface foroptical comparison with said chart, which comprises simultaneouslyr movingfollowers entirely across and in contact with opposite meeting faces of said object portion in the same transverse plane, withV one follower leading the other, and the paths of the followers crossing at opposite sides of-said object, and simultaneously scribing circular lines ofthe same diameters as said followers in the same order in a film on a light transmitting plate that correspond linv relative positions to the relative, crossing paths of said-followers.

3. In the method of comparing the profile contour of a selected portion of an object with a master chart of said portion and carrying thereon markings indicating permissible deviations therefrom, that improvement relating to the preparation of an outline of said surface for optical comparison with said chart, which comprises simultaneously moving followers entirely across and in contact with opposite meeting faces of said object portion in the same transverse plane, with one follower leading the other, and the paths of the followers crossing at opposite sides of said object, andi simultaneously recording on a film, in the same order and positions, lines corresponding to the successive positions of the followers in their relative path-s and similarly crossing.

4. In the. methodv ofv comparing the prolile contour of a selected portion-of an object with a master chart of said portion and carrying thereon markings indicating permissible deviations therefrom, that improvement relating Y to thepreparation of an outline of said :surface for optical comparison with said chart, which comprises simultaneously movingfollowers entirely across and in contact with opposite meeting faces of said object portion in the same transverse plane, with one follower leading the other, 

